The subject matter of this application relates to methods of implementing trickplay.
For many years programming viewable on a TV appliance has been broadcast by employing an analog video signal to modulate a radio frequency carrier and propagating the modulated RF carrier over a cable network. The analog video signals for different broadcast TV channels (commonly associated with channel names, such an NBC, CBS and FOX) are impressed on carriers at different frequencies. A receiver in the subscriber premises is tuned to the carrier frequency of the channel that is desired for screening. The receiver may be integrated in the TV appliance or it may be included in a separate device, such as a set-top box (STB).
Television programming and other multimedia content (MM content), including audio, video, graphics, text and data, may also be distributed using digital cable technology. In this case, the content for a given service (corresponding to a channel of the analog broadcast television domain) may be received at the cable network headend in the form of one or more packetized elementary streams that have been encoded in accordance with appropriate compression standards, such as the video compression standard that is commonly referred to as H.264/AVC. The cable network operator may distribute several services by organizing the payloads of the corresponding packetized elementary streams in transport stream packets that are delivered over the cable network physical infrastructure using one or more MPEG-2 systems transport streams. A cable network operator may also distribute digital audio/video (AV) content over the cable network physical infrastructure using internet protocol TV (IPTV).
In an implementation of IPTV, AV content for live TV channels is encoded and encrypted and is made available through an IP server, a delivery network (such as the cable network physical infrastructure or the cellular telephone infrastructure) and a home gateway to an IP client running on a computing device in a TV appliance or an STB.
Digital cable technology facilitates use of trickplay functions in presentation of AV content. A trickplay function allows the AV content to be presented at a different rate and/or in a different direction of evolution from the normal rate and direction of evolution. Thus, whereas AV content is normally presented at a rate corresponding to 30 video frames per second (fps) evolving in a forward direction, trickplay functions permit fast forward presentation at, for example, at a rate corresponding to two or four times (2× or 4×) the normal video frame rate and reverse presentation, i.e. presentation in the opposite direction from normal evolution at, for example, the normal frame rate or a rate corresponding to 2× or 4× times the normal frame rate.